1. Field of the Invention
The present disclosure relates to rotor drive systems, and more particularly to clutches for rotor drive systems in rotorcraft.
2. Description of Related Art
Rotorcraft like helicopters commonly employ rotor systems to provide lift. The rotor system generally receives rotational power from source of rotation, such as from a piston or turbine engine coupled to the rotor system through a transmission. Since the rotor system typically rotates at a slower speed than the engine, rotorcraft drive systems commonly include gearboxes for reducing the speed of mechanical rotation provided by the engine and transferred to the rotor system through the drive system. Under some conditions, such as during autorotation, it can be necessary to disconnect the rotor system from the drive system and gearbox using a clutch mechanism arranged in the force flow between the gearbox and the engine. The clutch mechanism is typically arranged at the gearbox input stage, where rotational speed is relatively high and torque is low, which allows for the clutch to incorporate a relative compact and lightweight arrangement like that of a sprag clutch. Such clutch mechanisms allow the rotor system to overrun the drive system rotationally. During overrunning, the clutch input and output members of the clutch mechanism maintain physical contact with one another, typically requiring a lubricant bath that cools and limits wear of the contacting members.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved rotorcraft and rotorcraft drive systems. The present disclosure provides a solution for this need.